Stack-Based Buffer Overflow in Tenda BE12 Pro

Executive Summary

CVE-2026-15693 is a stack-based buffer overflow vulnerability in the Tenda BE12 Pro router, specifically in firmware version 16.03.66.23. The issue occurs in the function fromSafeMacFilter of the file /goform/SafeMacFilter.

The vulnerability is caused by the unsafe use of the sprintf function to process the user-controlled page parameter without proper length validation. This allows an attacker to send input exceeding the fixed-size buffer (256 bytes), leading to memory corruption.

• The vulnerability can be exploited remotely without authentication.
• Exploitation may result in application crashes, denial of service (DoS), arbitrary code execution, or information leakage.
• A proof-of-concept exploit exists, demonstrating how an oversized page parameter in a POST request can trigger the flaw.

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Detection Guidance

To detect the CVE-2026-15693 vulnerability on your network or system, you can check if your Tenda BE12 Pro router is running the affected firmware version (16.03.66.23).

• Verify the firmware version of your Tenda BE12 Pro router by accessing the router's web interface or using command-line tools if available.

You can also attempt to detect exploitation attempts by monitoring network traffic for unusual POST requests to the `/goform/SafeMacFilter` endpoint with oversized `page` parameters.

• Use network monitoring tools like Wireshark or tcpdump to capture and analyze traffic to the router. Look for requests containing excessively long values in the `page` parameter.
• Example tcpdump command to monitor traffic to the router: tcpdump -i eth0 -s 0 -A 'port 80 and host <router_ip>' | grep 'SafeMacFilter'.

Additionally, you can use vulnerability scanning tools that support CVE detection to check for the presence of this vulnerability on your router.

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Impact Analysis

If you are using the Tenda BE12 Pro router with firmware version 16.03.66.23, this vulnerability could have serious consequences for your network security.

• Attackers could take control of your router, allowing them to monitor or manipulate network traffic.
• The router could be used as a pivot point to launch attacks against other devices on your network.
• Exploitation could lead to denial of service (DoS), disrupting your internet connectivity or network services.
• Arbitrary code execution could enable attackers to install malware, steal sensitive data, or create backdoors for persistent access.
• Information leakage could expose sensitive details about your network configuration or connected devices.

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Compliance Impact

This vulnerability could impact compliance with several common standards and regulations, depending on the context in which the affected router is used.

• GDPR (General Data Protection Regulation): If the router is used in an environment processing personal data of EU citizens, exploitation could lead to unauthorized access or data breaches. GDPR requires organizations to implement appropriate security measures to protect personal data, and this vulnerability represents a failure to do so, potentially resulting in fines or legal consequences.
• HIPAA (Health Insurance Portability and Accountability Act): If the router is part of a healthcare network handling protected health information (PHI), this vulnerability could lead to unauthorized access to sensitive patient data. HIPAA mandates strict security controls to safeguard PHI, and this flaw could be seen as a violation of those requirements.
• PCI DSS (Payment Card Industry Data Security Standard): If the router is involved in processing payment card transactions, exploitation could compromise cardholder data. PCI DSS requires secure network configurations and regular vulnerability management, and this vulnerability would likely be considered a critical risk requiring immediate remediation.
• NIST Cybersecurity Framework: The vulnerability undermines core functions like Identify, Protect, Detect, Respond, and Recover. Organizations following this framework would need to address the flaw to maintain compliance.

In all cases, the presence of this vulnerability indicates a failure to implement secure coding practices and proper vulnerability management, which are often required by these regulations and standards.

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Mitigation Strategies

To mitigate the CVE-2026-15693 vulnerability, follow these immediate steps:

• Check if your Tenda BE12 Pro router is running the affected firmware version (16.03.66.23). If so, look for an updated firmware version from the vendor and apply it as soon as possible.
• If no firmware update is available, restrict access to the router's web interface from untrusted networks, such as the internet. Use firewall rules to block external access to the router's management interface.
• Replace the unsafe `sprintf` function in the firmware with safer alternatives like `snprintf` to prevent buffer overflows. This step may require vendor intervention or custom firmware modifications.
• Implement strict input length checks and validate the `page` parameter in the `/goform/SafeMacFilter` endpoint to ensure it does not exceed the buffer size.
• Apply the principle of least privilege to the router's services to limit the potential impact of exploitation.
• Monitor network traffic for signs of exploitation attempts, such as oversized `page` parameters in POST requests to the vulnerable endpoint.
• Consider segmenting your network to isolate the router from critical systems until the vulnerability is patched.

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